I’ve just been alerted to a web page entitled “10 Great Minds Every Math Student Should Know”. It has short taster biographies of Newton, Erdős, Turing, Poincaré, al-Khwarizmi, Pythagoras, Descartes, Euler, Gauß, and Bayes.
Of course, if you want to know more about these or many other mathematicians, I suggest you try the St Andrews History of Mathematics site, and in particular their Indexes of Biographies.
For those seeking some insights into the minds of some famous mathematicians I would recommend the following list of books:
1) The Value of Science: Essential writings of Henri Poincare – edited by Stephen Jay Gould.
2) The Essential John Nash. -edited by Harold Kuhn and Sylvia Nasar
3) Euler The Master of Us All . – by William Dunham
4) God Created the Integers. – edited with commentary by Stephen Hawking
If I had to choose a favourite, it would probably be number 1.